/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *  (C) 2007 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */
#include "mpi.h"
#include <stdio.h>
#include <string.h>
#include "mpitest.h"

/* Check that Communicators can be created from various subsets of the
   processes in the communicator.
*/

void abortMsg( const char *, int );
int BuildComm( MPI_Comm, MPI_Group, const char [] );

void abortMsg( const char *str, int code )
{
    char msg[MPI_MAX_ERROR_STRING];
    int class, resultLen;

    MPI_Error_class( code, &class );
    MPI_Error_string( code, msg, &resultLen );
    fprintf( stderr, "%s: errcode = %d, class = %d, msg = %s\n", 
	     str, code, class, msg );
    MPI_Abort( MPI_COMM_WORLD, code );
}

int main( int argc, char *argv[] )
{
    MPI_Comm  dupWorld;
    int       wrank, wsize, gsize, err, errs = 0;
    int       ranges[1][3];
    MPI_Group wGroup, godd, ghigh, geven;

    MTest_Init( &argc, &argv );

    MPI_Comm_size( MPI_COMM_WORLD, &wsize );
    MPI_Comm_rank( MPI_COMM_WORLD, &wrank );

    /* Create some groups */
    MPI_Comm_group( MPI_COMM_WORLD, &wGroup );

    MTestPrintfMsg( 2, "Creating groups\n" );
    ranges[0][0] = 2*(wsize/2)-1;
    ranges[0][1] = 1;
    ranges[0][2] = -2;
    err = MPI_Group_range_incl( wGroup, 1, ranges, &godd );
    if (err) abortMsg( "Failed to create odd group: ", err );
    err = MPI_Group_size( godd, &gsize );
    if (err) abortMsg( "Failed to get size of odd group: ", err );
    if (gsize != wsize/2) {
	fprintf( stderr, "Group godd size is %d should be %d\n", gsize, 
		 wsize/2 );
	errs++;
    }

    ranges[0][0] = wsize/2+1;
    ranges[0][1] = wsize-1;
    ranges[0][2] = 1;
    err = MPI_Group_range_incl( wGroup, 1, ranges, &ghigh );
    if (err) abortMsg( "Failed to create high group\n", err );
    ranges[0][0] = 0;
    ranges[0][1] = wsize-1;
    ranges[0][2] = 2;
    err = MPI_Group_range_incl( wGroup, 1, ranges, &geven );
    if (err) abortMsg( "Failed to create even group:", err );

    MPI_Comm_dup( MPI_COMM_WORLD, &dupWorld );
    MPI_Comm_set_name( dupWorld, (char*)"Dup of world" );
    /* First, use the groups to create communicators from world and a dup
       of world */
    errs += BuildComm( MPI_COMM_WORLD, ghigh, "ghigh" );
    errs += BuildComm( MPI_COMM_WORLD, godd, "godd" );
    errs += BuildComm( MPI_COMM_WORLD, geven, "geven" );
    errs += BuildComm( dupWorld, ghigh, "ghigh" );
    errs += BuildComm( dupWorld, godd, "godd" );
    errs += BuildComm( dupWorld, geven, "geven" );

#if MTEST_HAVE_MIN_MPI_VERSION(2,2)
    /* check that we can create multiple communicators from a single collective
     * call to MPI_Comm_create as long as the groups are all disjoint */
    errs += BuildComm( MPI_COMM_WORLD, (wrank % 2 ? godd : geven), "godd+geven" );
    errs += BuildComm( dupWorld,       (wrank % 2 ? godd : geven), "godd+geven" );
    errs += BuildComm( MPI_COMM_WORLD, MPI_GROUP_EMPTY, "MPI_GROUP_EMPTY" );
    errs += BuildComm( dupWorld,       MPI_GROUP_EMPTY, "MPI_GROUP_EMPTY" );
#endif

    MPI_Comm_free( &dupWorld );
    MPI_Group_free( &ghigh );
    MPI_Group_free( &godd );
    MPI_Group_free( &geven );
    MPI_Group_free( &wGroup );

    MTest_Finalize( errs );

    MPI_Finalize();
    return 0;
}

int BuildComm( MPI_Comm oldcomm, MPI_Group group, const char gname[] )
{
    MPI_Comm newcomm;
    int grank, gsize, rank, size, errs = 0;
    char cname[MPI_MAX_OBJECT_NAME+1];
    int  cnamelen;

    MPI_Group_rank( group, &grank );
    MPI_Group_size( group, &gsize );
    MPI_Comm_get_name( oldcomm, cname, &cnamelen );
    MTestPrintfMsg( 2, "Testing comm %s from %s\n", cname, gname );
    MPI_Comm_create( oldcomm, group, &newcomm );
    if (newcomm == MPI_COMM_NULL && grank != MPI_UNDEFINED) {
	errs ++;
	fprintf( stderr, "newcomm is null but process is in group\n" );
    }
    if (newcomm != MPI_COMM_NULL && grank == MPI_UNDEFINED) {
	errs ++;
	fprintf( stderr, "newcomm is not null but process is not in group\n" );
    }
    if (newcomm != MPI_COMM_NULL && grank != MPI_UNDEFINED) {
	MPI_Comm_rank( newcomm, &rank );
	if (rank != grank) {
	    errs ++;
	    fprintf( stderr, "Rank is %d should be %d in comm from %s\n", 
		     rank, grank, gname );
	}
	MPI_Comm_size( newcomm, &size );
	if (size != gsize) {
	    errs++;
	    fprintf( stderr, "Size is %d should be %d in comm from %s\n",
		     size, gsize, gname );
	}
	MPI_Comm_free( &newcomm );
	MTestPrintfMsg( 2, "Done testing comm %s from %s\n", cname, gname );
    }
    return errs;
}
